Search for 100LL replacement raises many questions

When I started to write this post on unleaded avgas, I sat down to read about the upcoming evaluation program for four candidate fuels. The more I read the more questions it raised.

For instance, why does Swift Fuels have two candidates?

But the biggest question concerned the percentage of the piston aviation fleet that the new candidate fuels will satisfy. A few questions arise, like which engines are the most critical, under what conditions will they knock, which airframe, propeller, operating conditions are most critical, and on and on.

For example, if an engine runs knock free on a candidate fuel in a test cell in New Jersey, will it also run knock free in a hot, dry climate with a bigger prop and an overloaded aircraft?

And what about testing orphan aircraft or big radial engines? Are they going to test a 3350? If so, at what boost pressure and rpm?

What margin of safety is there? If someone is using the new fuel and has their timing advanced more than specified, will they have problems? What about exhaust valve recession in newly overhauled engines?

This is like doing an algebra test with 36 unknowns and only two equations.

Then when they determine what percentage of the planes will be satisfied by the new fuel, what do you do with that information? If they have a fuel that satisfied 99% of the fleet, how can you be sure that your plane is part of that 99%? If it isn’t, what do you do? This may sound minor, but I think this is going to be one of the biggest problems if one of these candidates ever reaches the marketplace.

Another big problem is going to be cost. The cost projections I have seen seem unrealistic. People keep saying that there will be a huge cost savings because the fuel will be able to be shipped by pipeline. There will be some cost savings, but because of the cost of the product and the small volume, the loss from the interface will limit pipeline usage to only large shipments. Most of the shipments will still be by truck or rail.

And then there is competition. If they only approve one fuel, who will be able to sell it? If they only approve one, does anyone out there believe that the company selling it will keep it at minimum cost? Or will it write a spec around the new fuel and let other companies produce the product?

And what about 100LL? Will FBOs need two fuel systems because there will be a time when the new fuel and 100LL will both be available? In the switch over, do they plan on outlawing 100LL? If the new product and 100LL are both available, will they force FBOs to handle both?

No matter how they do it, it is going to be messy.

And then there is mogas. If the new product is much more expensive or has problems, will more pilots switch over to mogas, which could reduce the volume sales of the new product to an almost uneconomic low level?

What about the storage stability of the new product? 100LL is very stable and people store it and then use it a year or even several years after it was produced. This is especially true in northern climates where the supply line is very long. Will the new product store as well or will it form gums and or take on moisture?

And the questions go on and on. For when all is said and done, much will have been said and little will have been done.

Comments

More damage is done to the environment every day by the contralls at 30,000 than in a full year of flying by the entire GA fleet. The amount of sunlight blocking via contrails over the entire globe is huge. And the thermal change from something like -30 deg to 700 deg in a 12 foot column is huge. And there appear to be changes in the particulate matter in the jet exhaust. In the US it is a dirty secret. In Europe, there are fees or penalties for flying above 30,000 feet because the damage is documented.

Yeah, cool. Let’s get rid of the jet airliners. They charge too much for bags anyway and treat you like cattle and you can’t really get to where you want to go without way too much expensive parking and final transportation. Alternatively, how about an 8 engine Rotax powered transporter that burns mogas – no expensive fuel, no contrails, no ethanol, no lead, and no airline pilot’s union to boot —- now that’s progress………………

It seems to me that if one Pareto’d Lead contributors to the environment that 100LL wouldn’t be near the top of the list. I’d be willing to bet that China and other industrial sources make the contribution of 100LL pale by comparison.

Are we going after the low hanging fruit simply because it is easy to vilify, or is 100LL near the top of the list? Please show me the facts. If it is a major contributor, let’s press on with a replacement solution sans Pb. If not, let’s leave well enough alone till it is aged out of the market by other technologies.

A substitute for 100LL will only accomplish getting the lead out of the fuel which satisfies only the “evironmental whacko’s” and that’s their motivation. While eliminating the lead is not a bad idea that alone doesn’t do the average airplane owner much to be happy about except from the standpoint that the plugs might not get dirty as quickly. Accordingly, it is contended that a search for a replacement fuel is not necessary, may take forever to come up with, and would most probably cost the same if not more than 100LL so why do it? It isn’t worth it. Just get a blanket certification for mogas and be done with it. Everything else simply gets opportunists the ability to extract money from the government for testing and ultimately a costly product to boot. If then there are still aircraft out there that need anti-knock additives or those with soft valve seats or high compression engines then just make an Airworthiness Directive to force them to add the lead or whatever to the fuel tank at every refueling. Now that’s a real solution and it would reduce our costs of flying tremendously.

Hi, I ran my luscombe 8 A/E for 3000hours on mogas with no ill effects. I ran my Twin Beech for many years and the 985 Pratts ran better and smoother than they did with 100LL. I ran my Cessna 195 Jacobs B2 the same way, with no ill effects, using 100LL only when i had to. I ran the 540 in my skybolt on 100LL because i was a part of a syndicate and it was the syndicates policy to run on 100LL. My opinion is that with a decent electronic ignition system, which should be able to deal with any detonation issues, mogas should be just fine. There are additives available if need be for the folks who require them, Russ.

Ben, Your comments are extremely negative. Why do you not think that all your questions will be answered before a new fuel is approved. Your article suggests that you are in favor of poisoning the atmosphere with lead.

Kent you wrote ” What the FAA is doing is precisely the same as our White House – leading from the rear.” Unfortunately your political leanings and rhetoric cause you to lose all credibility. I don’t care what side of the political spectrum you lean towards, that is your opinion, but to constantly interject your political opinion in a decidedly non political subject leaves me to wonder why.

To Ray, what does his picture have to do with anything? A subtle form of bullying. I don’t think he is looking for a job.

Folks if you want your comments to be taken seriously, take the subject seriously, keep it civil and on subject.

Really disappointed in this article. Kent Misegades (comment above) covered the real issue the best. This article appears to be a blatant attempt to keep 100LL alive when the truth is the market best determines what fuel will be used. Just increase the taxes on 100LL until demand is reduced until only high performance WWII aircraft use it, because the number of aircraft that use 100LL is already greatly reduced and becoming less every year.

Ben Visser and Todd Petersen are the two leading experts on this topic, but are not in the inner circle on this tired old search for the mythical drop-in replacement for 100LL, a fuel needed by less than one out of five airplane owners of our rapidly aging fleet of piston aircraft. One wonders why they were not paid by the FAA to lead any effort? The fact is, the whole world outside the US and Canada has already shifted to a two fuel solution of mogas and Jet-A. What the FAA is doing is precisely the same as our White House – leading from the rear.

Your comments are interessting but very late. Early last year the FAA and its contributing organizations presented the test plan for unleaded fuel test and evaluation. Why didn’t you make your suggesions then?

Are not 100LL and the new fuel to be compatible?
Is not the formula that is approved to be available to all producers?
You mention cost as a threat, but do not say what you expect…misleading!
I see your picture, you look untrustworthy, I would not hire you.
What do you need to prove?

The questions from a critical expert are absolute necessity, like certain cable news networks being critical in analysis because others are bent to not be critical of newsworthy issues. Great part is Mr. Visser as an expert raises the caution flag for all of us that think 6.00 gallon fuel or more is stifling the majority of airplanes from being flown. He has no dog in the hunt.